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Current Limit Detect Following

Every Shunt Voltage Conversion

Bus and Power Limit Detect

Following Every Bus Voltage Conversion

Power Average

Bus Voltage Average

Shunt Voltage Average

12

INA231

SBOS644B – FEBRUARY 2013 – REVISED AUGUST 2017

www.ti.com

Product Folder Links: INA231

Submit Documentation Feedback

Copyright © 2013–2017, Texas Instruments Incorporated

Feature Description (continued)

Figure 21. Power Calculation Scheme

In addition to the current and power accumulating after every sample, the shunt and bus voltage measurements

are also collected. After all of the samples have been measured and the corresponding current and power

calculations have been made, the accumulated average for each of these parameters is then loaded to the

corresponding output registers where they can then be read.

8.3.1.2 ALERT Pin

The INA231 has a single Alert Limit register (07h) that allows the ALERT pin to be programmed to respond to a

single user-defined event or to a conversion ready notification if desired. The Mask/Enable register allows for

selection from one of the five available functions to monitor and set the conversion ready bit (CNVR,

Mask/Enable register) to control the response of the ALERT pin. Based on the function being monitored, a value

would then be entered into the Alert Limit register to set the corresponding threshold value that asserts the

ALERT pin.

The ALERT pin allows for one of several available alert functions to be monitored to determine if a user-defined

threshold has been exceeded. The five alert functions that can be monitored are:

•

Shunt voltage overlimit (SOL)

•

Shunt voltage underlimit (SUL)

•

Bus voltage overlimit (BOL)

•

Bus voltage underlimit (BUL)

•

Power overlimit (POL)

The ALERT pin is an open-drain output. This pin is asserted when the alert function selected in the Mask/Enable

register exceeds the value programmed into the Alert Limit register. Only one of these alert functions can be

enabled and monitored at a time. If multiple alert functions are enabled, the selected function in the highest

significant bit position takes priority and responds to the Alert Limit register value. For example, if the SOL and

the SUL are both selected, the ALERT pin asserts when the Shunt Voltage Over Limit register exceeds the value

in the Alert Limit register.

The conversion-ready state of the device can also be monitored at the ALERT pin to inform the user when the

device has completed the previous conversion and is ready to begin a new conversion. The conversion ready

flag (CVRF) bit can be monitored at the ALERT pin along with one of the alert functions. If an alert function and

the CNVR bit are both enabled for monitoring at the ALERT pin, then after the ALERT pin is asserted, the CVRF

bit (D3) and the AFF bit (D4) in the Mask/Enable register must be read following the alert to determine the

source of the alert. If the conversion ready feature is not desired, and the CNVR bit is not set, the ALERT pin

only responds to an exceeded alert limit based on the alert function enabled.

If the alert function is not used, the ALERT pin can be left floating without impacting the operation of the device.